although i've come upon this thread somewhat late, i must say that i do not recommend sugino rds at all. they flex a lot. i even noticed the flex before i had ever tried anything else for comparison. rds are road cranks, plain and simple. they were used on the bianchi pista in '05, but are not at all singlespeed or fixed specific. my friend uses my old set on his road bike.

in any case, my point is just that, if you want to buy road cranks and a bottom bracket to get you going for now, i would really advise picking up a pair of older shimano 105 or 600/ultegra road cranks rather than some faux-track crap like the rd. you'll find that the shimanos are substantially stiffer. you will certainly be able to find a nice used set that you can use with a cheap shimano un53/73 107mm sealed bottom bracket for a decent track (42-43mm) chainline. if you go that route, the set will almost certainly have a 42 tooth chainring, which will give you a good starting ratio with a standard 16 tooth cog in the rear. you just take off the larger ring, buy some single stack chainring bolts (since you will only have one ring now) and you're golden. total investment will be about $55-$75 - probably $30-40 for the crankset, another $25-35 for the bottom bracket. this will get you riding, which is what matters.

then, when you decide to pick up sugino 75s (they are the way to go to maximize quality:cost ratio), you will be able to keep the 107mm bottom bracket that you have until you can later afford the proper 109mm sugino bottom bracket (or, alternatively, the shimano dura-ace 109 square taper cartridge.. or, the ultrabling hatta). it will allow you to upgrade when you can afford to, instead of having your frame sitting in the corner for a few more months.