I did my first 10-day meditation retreat at Kopan monastery in Nepal in late Jan/early Feb this year. http://www.kopan-monastery.com/
I tied it in with a roughly 1 week stay in the monastery prior.
The retreat itself was lead by Ven. Antonio Satta, who was scholared by Geluk lineaged teachers but is trained in Vipassana from the Mahasi Sayadaw Insight Meditation Centre. The practice was Vipassana with a very small smattering of information concerning Mahamudra. He's running another retreat in Kopan in January 2011.
The monastery itself is associated with FPMT but the retreat was a Vipassana retreat. Ven. Antonio has been taughed by Mahayana lineaged teachers but has also trained in meditation at the Mahasi Sayadaw Insight Meditation Centre, so brings a unique blend of experience and perspective.
The monastery is extremely well-resourced (shop, cafe and Internet access on site, some currency exchange and monks that speak excellent English), has very good accommodation and is well equipped to cater for Western guests and meditators. It is also quite accessible from Kathmandu (a city you'll want to spend as little time in as possible IMO).
So it is possible. I stayed in Nepal for a month and combined this with a trek around the Annapurnna region post-retreat.
I highly recommend the course, and the monastery is well-equipped to support such a retreat. Around 70 Westerners attended, though numbers declined as the retreat continued. It is conducted in full silence, communication devices are surrendered and the monastery provides vegetarian food only. Just be mindful that the monastery itself is Mahayana, though that has little influence when you're attending the retreat itself.
Hope this helps. Any questions, PM me.