I think "conglomerate.net" would be a much common synonym (read:more value) than "amalgamation.net". Even "amalgam.net" would be better. Not as bad as "gondwanaland.net" (the ancient supercontinent), but moving in that direction (length, typo potential). I think it has some good excitement to it though, and it IS a dictionary word.
I personally think that domains that focus on things "coming together" or a "convergence" are very handy and can have a multplicity of uses. With so many universes coming together nowadays, I think Amalgamation.net might have a decent future (shame its so long though).
$250
~ W|Z