Just started reading the forum so this reply might be a little late...
I'm a volunteer at the Colling's Foundation at Ellington Field in Houston. We do have an F-4 that has been repainted to the condition of General Richie's at the end of Vietnam.
So.....what I know about getting one for private use. It ain't easy. The plane itself has to come from the boneyard so you have to be able to convince the AF to sell one to you. Then you have to convince the FAA that you have a legitimate reason for wanting it (not too easy, especially post 9/11). Next comes the huge task of returning it to flying condition since it's been sitting around for at least ten years. Not only that but there are a bunch of regs that must be followed. The navs and coms have to be converted to civilian use, plus something (I forget what) has to be modified in order to prevent supersonic flight, the radar has to be disconnected, the weapons systems disabled, etc. Then there is the standard maintenence. There is a dedicated group of volunteers that work every weekend to keep it maintained. It is a ton of work. You definitely need an old crew chief or someone w/ significant F-4 experience to keep it running regularly. As everyone else has mentioned the J-79s suck down fuel like no other so a platinum credit card is a must. I've met a couple at Ellington that own a pair of Mig-21s (that's right, a couple....they have a 'his' and 'her' jet) and they are only able to get them up about twice a year with the fuel and maintenence costs. Those don't burn gas at near the same rate so the F-4 bill would be HUGE! Then, you have to get someone from Martin-Baker to come down every so often to check on the ejection seats. The list goes on and on....and on...and on.
But, it is defintely one of the most beatiful and awesome planes I've ever seen and is very formidable to stand next to. If you have one of those trees that grow money that my dad said didn't exist then I guess it might work if you could get past the FAA.
Football season is on for me now so there isn't much time for me to go volunteer. However, if anyone has any specific questions about this let me know 'cause I think I'll be there next week. Oh yeah....the hydraulic system is a nightmare too.
Seems to me that if you want the adrenaline of afterburners an old Mig might be the way to go. I hear they cost somewhere in the neighborhood of 2-3 hundred thousand (not sure about that, just hangar gossip). Not cheap, but better.