I have a set of record cranks that I converted to fixie use using one of these chain rings:
I can sell the chain set for the price of the chain ring £35, so you basically get the cranks for free (they are rather worn) the chain ring is 'as new' ? <200 miles. I'll also chuck in a Veloce BB which seems to give the right chain line with the record cranks.
For some other bits you might find useful for a cheap fixie build check my 'For sale thread'
Got a Continental Gatorskin thats going too and a pair of cheapo Joytech fixie wheels too that aren't listed yet.