Has anyone been able to get a Sierra Aircard 710/750/755, which is
a wireless GSM/GPRS PCMCIA card.

This card has decent Linux support:

    http://www.sierrawireless.com/SupportDownload/ac7x0_linux.asp

which includes a Linux serial driver that allows one to run ppp
over it.

Previously there were a few postings about Sierra Aircarda on
the NetBSD mailing lists, but no one mentioned if they could get
it to work.

Alicia.