You could do most of what you're talking about on a V-strom too. Or the 1200 Tenere that is coming out.
I'm not familiar enough with the BMW to make any recommendations there.
The KTM Adventure is
like a big dirtbike. If you've got the skills it can provide some good overlap with your 450.
2011 KTM 990 Adventure R
2010 KTM 530 EXC
2009 KTM 950 Super Enduro Erzberg Edition