I'm not really from here in Omaha, NE I am from TX but I moved here 6 months ago because I am in the airforce and I'm a navigator on the type planes we have here. Yes the RV's are great planes as well and I have flown the 8 and the 4 and I must say Way Cool. But most people I know that have built the 4/6/8 all spend well over 45 or 50k. You may build one for that from plans only but that would take forever or much longer than the planes I mentioned earlier and would probably involve a used engine or minimum VFR instruments. If I were really wanting something like the RV but not spend as much, just buy a Thorp T-18 (flown this one too) because you can get a really nice one for 40k (already built though). All planes that have been spoken of are great planes it will just depend on what you want out of it and how much you want to spend. If you haven't yet, look on barnstormers.com to get a feel for how much each one costs after they are built.
Lee