Considering that you haven't done a frame swap before, have limited work space and tight budget, this is what I'd do in that situation:
First, look at what is local and the rust/condition. Then check similar beginnings from further away if rust is common. 500 to 1K on shipping can save that and more in rust repair unless you do it yourself.
Some candidates:
74-78 Dodge PU with the 440 swapped in. These can often be bought under 2K, with the rest spent on safety and swap parts. A quick paint job and recover the bench seat or buy a pair of buckets.
http://www.jcwhitney.com/smittybilt-front-low-back-bucket-seats-for-jeeps/p3091021.jcwx You should be able to pull this off in a year or less easy, and you don't see them out much any more. Extra points for a nice lowering. Both the engine swap and the lowering have threads here on Moparts. Bonus with IFS and disc brakes without swapping.
If inspections are not a concern (safety/smog), try to find a later model
1. that will take a small block swap. D50/Arrow pickups would be a good bet and could start as a sleeper and if needed, progress to a tubbed pro-street mini truck. Trade your stuff for Small block stuff.
2. a RWD car from the 80s with your big block swapped in. Sleeper 5th Ave. or an Imperial with NASCAR style (done by a member here years back). Again, stuff like suspension, brakes and steering do not need replacement, just possible repair.
The last one requires more space than you have, but can provide great results, but need more labor and time - take two and make one.
This is where you get a running donor (Dakota or Ram V8) and a body in decent shape in the style you like. This is the basis of Poorboy's car and Ron's trucks. You will need some good skills and space to pull this off. The budget will only work if you can sell off every unused part.
Up through the 50s, the 6V positive ground will cause a lot of hidden expense, unless you are willing to rewire, upgrade the brakes and do the full drivetrain swap. Flathead-only cars (30s thru early 50s) have intrusive steering columns, making small block swaps much more feasible. Your big block can fit in mid to late 50s cars that had V8s.
The early trucks are simple, but if you are going to use 440 torque and HP, you need to consider upgraded brakes and at least fully rebuilding the stock suspension and steering. Upgrades there will make it much more pleasant and manageable.
The most important thing is to find the project that really sparks your interest long-term, because if you settle for something that is just the best you could find or is not really what you wanted, there will be a time when you can't see the light at the end of the tunnel and that spark is the only thing that keeps you from closing the door and walking away.
EDIT
If you could live with a rough car (take a look at Stu's thread
HERE ), you could buy
THIS , make it solid and safe (brakes/steering) and toss your parts in. Paint it up like the Roadkill Charger or Petty Blue with big 43 on the side. Think field rescued ex-race car.
ROADKILL EDIT 2
some examples here in AZ
D50 $1000 75 PU WITH 440 $1000 74 400 PU $1900 34 cab for the D50 like Ron's $1400 
