I would be very interested in relocating tank. But I would think Formula exhasted all other options before locating there.
A smaller one in a different location would be fine. I'll try & look up cpacity vs. reg style heads.

I have a 1991 292 and my system looks the same but there is no tank in the engine area, but there is the thru hull fitting as mentioned, but how do you control the system as far as dump at sea or at the dock?

There should be a Y valve so you can either dump overboard (illegal?) Or you can pump it out @ local marina....

I would seriously exhaust every other option of relocating what you need to before ditching it completely. When working properly they work really well, and even though it may not be used all that often, it is nice to have toilet on board.

Although many consider the numerous negatives of having a fixed, complex onboard head system acceptable, I would prefer a simple, removable head to be a plus.

One of the main requirements of a boat when I was shopping last year was vacuflush. And I love having mine.

I moved mine to the starboard side. It tucks away and just clears the header. I put a slight angle into the mounting platform to get the clearance I needed. Works great there and is no longer in the way...

Might be on to something there... Have any pics?

Complex? It's a toilet with a vacuum holding tank. Not rocket science......wait, I think they do use a vacuum on the space station. Hmmmm..... :D :D