Looks like there's regression or something. I've encountered problems from bugs 55916 and 70867 bug didn't find a way to fix it. Turning on debug mode in mono shows, there's unresolved symbol XML_ParserCreate. I've tried both versions 1.0.4 and 1.0.5 without any change... :-( I don't know what info may be useful for you, so please ask me...
Please try libgdiplus-1.0.5-r1 in portage. I've added an "autoconf" to the src_unpack, which should get the libtool version stuff fully in sync. Please report back any success/failures. Thanks.
Seems to be working. Gimme some more time to test it thoroughly...
Nice work. Closing...