Sounds like you are on the right track. As with all racing, function trumps form. And generally speaking, form costs extra.
You will probably fiddle with your fitting for a while since this is new to you. A threaded to threadless adapter will make fitting a bit easier and give you a lot more stem options. Plus, if you find that you need a 90mm stem instead of a 100mm, you can go to your local bike shop and get one for cheap instead of the harder to find quill stems. Threadless stems are flip/flop giving you more fitting options. Once you get your geometry settled, then maybe buy the quill stem that makes the right dimensions for the bike for you, and buy it once.
Mountain bike pedals (Time ATAC, Eggbeaters, Candy, SPD) are generally frowned upon at many tracks because they are relatively easy to disengage from. Popular options are SPD-SL, Speedplay, and Look.
You don't *need* track bars. The majority of the bars that you will see on the track are road bars. Just make sure they are strong, at least made of heat treated aluminum to take the stress of standing starts.
Most people run crank arms up to 170mm. 175s are uncommon on the track. It really depends on the steepness of the track and the pedals you choose. A flat track can easily be ridden with 175s.
Tubulars aren't a requirement. More of a luxury being that one doesn't have to worry about debris to puncture the tire and the high PSIs that you can get. But, 120PSI of clinchers is fine. Do, however spend the extra bucks on a quality tire.
A lot of questions (crank length, pedals, tires) can be answered by the regulars at the track.
You have been given really good advice by Carleton. I started racing on the same frame that you are building up. I would advise that you find another frame. That particular frame had a nasty tendency to flex wildly when sprinting. Now, I was a match sprinter, so the problem might have been more pronounced than it would have been for a pursuit type, but you would still notice a lot of inefficiency in your standing start. Plus, it didn't seem to track all that well. Even in a mass start race, when I would hit the gas, the rear wheel would move around a lot. The guys I was racing with would typically give me a wide berth coming out of turn 4 in the final lap, and more than one told me it was scary to ride behind me. As soon as I could, I changed bikes. There are many steel frames you could find that would work better. Just my opinion.
I am sort of in the same boat as you, except I'm a season into the whole experience. I was essentially brand new to track racing in August 2008, then raced May-Aug 2009, maybe 10-12 times. I had two prior track days in the early 90s, kind of a "into the deep end" bit. Those were the only two days I'd ridden a fixed gear bike outside prior to my race in Aug 2008.
This is what I've found.
The Omnium cranks are fine. It appears, looking at my bike, that that's what I bought (I just ordered the cheapest track cranks out there - they cost the same as a chainring, so I just got a crankset instead of a 48T).
I'd get multiple chainrings - find out what people there use and go up and down a tooth. Racers at the "local" (it's 3 hours away) track generally use an 88-90" gear (49 or 50 x 15). I use a 50x15, and I'll be trying a 49 and 51. The 48T that came with the cranks - I couldn't spin fast enough to stay with the group.
If you're lucky and can afford a second rear wheel, get one with a bigger cog. In my example above, I'd get a 16 or 17T. This is so you can warm up. Or, if you have room, you can ride your bike on rollers. A flipflop wheel works.
For wheels, being able to spin up is good. Top speed is less relevant (at least where I race). I can't go nearly as fast on the track bike as on the road bike - in fact, my top speed on the track bike is what I'd consider to be a relatively slow leadout on the road bike. Therefore it makes sense that I emphasize acceleration over top speed.
I use a front aero wheel, mainly because my problem is in finishing races. An aero wheel ought to save me some energy, at least that's what I figure. You can use most road wheels if you have a "track skewer" which has no lever; instead it has something like a hex head on each side. Next year I'll use one of my road front wheels for track racing. I'll focus on getting track rear wheels since I only have one, and it's a light rim built heavy (2.0 straight gauge spokes). I want to rebuild it with an aero rim (Zipp 440), and then hopefully get a second wheel (or, preferably, a second complete bike).
Nothing wrong with quill stems. They're quick to remove, they don't require headset adjustments, and you can easily carry a few around. Problem is swapping bars etc. I have a few quills and I figure I'll set one bar up for time trials (pursuits, maybe kilo). I'll use the setup I have now otherwise (crit bend road bar).
My bike, kinda sorta (it changes):
I haven't noticed that this frame is overly flexy on the track last time I was there. (I have gone a few time to just ride there with a group of friends) And I would really like to use this frame for a bit just because I don't have a bunch of cash to throw at a bike yet.
But thanks for the tips on the wheels and cranks. I'm going to keep looking for some Omniums.
I'll have to talk to they guys at the track about the pedal/shoes issue. Right now I have a few sets of SPDs that I have collected of the years and one set of atacs. And for shoes I have some dom 4s. I would really like not to have to buy new pedals and shoes but that's a question they can answer.
And Carleton that was my thoughts on the threadless adapter. Get my fit how I like it then buy one quill stem and tape or put the grips on the bars for good. (well till something needs to be changed again.)
Thanks for the tips guys.
I'll get some photos up of the bike once all the parts come in and I paint it. the paint is crap right now, and I can paint it for free at work so there is no cost there. Just the time it will take to choose a color.