I ride with a front brake on my "bumbikes". I used a bottom bracket lockring to follow the track cog on the hub - adds a bit of resistance against the cog unscrewing, but it's not a track hub. I also bought a cheap cog so I wouldn't care much about it, then I used lots of loctite and some jb weld (maybe it helps, maybe not - peace of mind!), and I really cranked those suckers on there. Redishing and truing really isn't that hard - just read what Sheldon Brown has to say about it and you'll be set. I'm not going for perfection, I'm going for usability, so I don't have any special tools for the job.

27" wheels are plentiful and dirt cheap, so if I want a different gearing I'll just do the same thing with another wheel -- goodwill here ALWAYS has a 27" complete bike for under $10 - that should get you a rear wheel, bottom bracket lockring, and another spare tire salvaged off the front. If it were a decent frame in my size, I may just convert that bike and go buy another bottom bracket lockring for the hub -- then ya don't have to swap any parts to change gearing, just grab a different bike. My 2nd bike was bought for parts, but I ended up liking the ride.

Even buying from a pricey LBS (cog and bb lockring), I'll bet you could do a build for under $60. My last one cost $30 total, thanks to eBay.

Good luck!