I have to agree with David that the stock Trillium
windows are very desirable and should be kept.
However, if I were looking to replace them I would start
by looking at the Hehr line of windows. That company
will fabricate just about anything you might want.
Unfortunately, it looks like most windows available
have radiused corners and would require making a larger
cutout and fabricating a new plywood frame around the
opening to hold the mounting screws = big job. Also,
the cost of such windows would probably be $300 to $500
each (guess). The 7900 series looks like it might fit the
bill. I too, wonder why you want/need to replace the
Looking a Hehr windows I noticed that the 7900 series has
been superceded by the 8700 series.
Hehr RV Motorhome windows, Hehr window parts