We're having a lot of fun with the 3D printer and ended up ordering a Mendel Max 2.0 beta (more on that later) as well as another Mendel Max 1.5. This time around our plan is to really customize the MM1.5 printer and see what we can do to reduce the part count, improve the looks, and perhaps improve some functionality. The main thing that annoys me with the MM1.5 and most Reprap printers is the triangle top. It's not really needed, adds extraneous parts, and makes the printer feels more cluttered. Everyone that's seen our printer likes to watch it print, so it'd be nice to open it up and improve viewing angles.
The first step was to get rid of the triangle top. While it's completely possible to just remove the entire top section of the printer frame and have the Z travel rods attached only to the bottom frame with no connections up top, we decided to borrow from the design of the MM2.0 and went with vertical extrusions to support the Z rods up top. I designed some custom brackets to attach the rods at the top, and some right angle brackets to support the vertical extrusions along the base. Here's what we've got so far. (Custom parts are purple.) You can get the right angle bracket model from http://www.thingiverse.com/thing:59398