I balk at those prices - Andrews Comms sell 80mm * 20 triplets (BAK4 prisms - fully multi coated for around $199. Owning a pair I have to say they are excellent. Weighty - but that is their only drawback.
http://www.andrewscom.com.au/site-section-11.htm
Otherwise the 70mm by 11 magnification ones at $129 - weighting half of the triplets would be very useable.