I purchased a nice small block Top Loader with a like-new Hurst shifter from a fellow Forum member that had converted to a T5 for $750. The pedals from EBay for about $75. The flywheel for about $50. The bellhousing, Z-bar and linkage for about $150. I think you can still do this swap for less than $1,200 plus the cost of a new clutch set if you look hard enough. Lots of guys are going to a T5, so Top Loaders are not that hard to find. Just make sure you buy the trans from a working car and from someone you know or trust.
If it were me I would put in a T5. Sending a toploader out for rebuilding from one of the reputable shops (David Kee, Dan Williams) is going to cost you $600-900 if it has any internal problems at all.
Buy a brand new T5 for $1250 and you have the OD which really frees up your choice of rear gear ratios.