Well thanks for all of the input guys. Based on all of the advice everyone has given me I've come up with a tentative plan. I think this may work, I'd like to know what you all think. I'd also like to solicit any suggestions or further advice you all might have to offer for this. I'm going to have to sell some fish, but I think I'll be able to keep the ones that are special.
Thanks everyone.
Here's the tentative plan:
1- Upgrade the electrical system as best as I can in order to handle the draw of the tank. If I can cut down the pull of the tank buy shutting down some filtration, this shouldn't be too big of an issue.
2- Cut down on filtration. I am currently obscenely overfiltered and the level of filtration I'm using is likely entirely unnecessary. So, I'm planning to cut down my huge pool filter, my AC100, my Marineland 60 pothos colony, my Magnum 350 and four of my six 1200+ gph powerheads. But to do this, I have to:
3- Cut down on stock. As it sits right now, I desperately need to transition my fish into the 510 for them to continue to thrive. Considering how long its taken me to make progress on building the tank, there's no point in actually putting it up now just to tear it down in 3 months or so. So in order for my fish to thrive, and since they're going to be stuck in the 150 for the time being, I need to get rid of some fish. This has been an incredibly hard realization for me to come to and has involved some very difficult decisions. I've decided that I'm going to keep Max the gatf and Dottie the goonch. Dottie doesn't really do much of anything and I think she could stay with Max for now with a minimum of consequences. However, it won't be too long before Max needs a bit more swimming room. So,
4- I'm going to have to upgrade to an intermediary tank. It is readily apparent that one can get a 240 with a stand for about $300 if you're patient. It doesn't have to be pretty for me, it just needs to hold water. Obviously this isn't ideal for the gatf, but I feel that I could safely get him up to ~20" or so in this tank if I keep it focused to his needs (which I certainly intend to do). I feel it'll take a couple of years before he gets there anyway so hopefully I'll be back in a house of my own with room to play before it ever comes to that. An 8x2 footprint is the largest I could actuallly manage to get into the house.
I hope all of this works out. The last thing I want to have to do is a GATF for sale thread!