Let me again suggest using a Kobo mini e-reader running XCSoar. The screen is black and white but is very readable in sunlight. You can make one up for $100 or a little more if you can't make the internal connections yourself.

I have made six of these for myself and other club members. Not as high end as the commercial products, but way better than any Ipag.

Directions are on the web, this one is a good starting point.

http://www.50k-or-bust.com/Kobo%20XC...Notes%2001.pdf

Gary