Wow, Mike. 4x8 is really big. I would see if you can't sell it to a sign shop. They actually use presses that size and will have the trucks to pick it up! And if you sell it to someone local, it will be close by if you ever need it. There aren't many things you can't mount on a Seal 500.
I have been selling off things I don't use much, more to reclaim the real estate than the dollars. Most of my tools & equipment were used or have been fully depreciated. I haven't missed anything yet, for what that is worth. And I have a little spare cash for that odd thing that comes up for sale. (I am something of a tool junkie even though I didn't bid on that mat smacker).
A couple of years ago someone on the G was trying to give a 4x8 heat press away. Just moving it was more than it was worth. But a vacuum press has other uses and should be more marketable.