The LCD is nice, sure. The PowerBook Mustang is somewhere between a 5300 and a 1400. (Interestingly, my copy of "AppleDesign" shows a picture of a Mustang with a PowerBook 5400 production badge.) In fact, it's pretty much the same as a 1400c/133 in a more compact case and without a CD-ROM. It even has 256kB of L2 cache, though I could never get the L2 working on my Mustang. OS 8.1 and 8.6 didn't recognize it. I never tried a version of System 7. Maybe something in the 7.5.x region would work.
Here are some pictures of my Mustang:
Pictures
Here's my small collection of interesting Macs:
Sorry, the picture was taken on my phone, so it's a bit crappy.
The Mustang is open on the 1st shelf. Beside it is a prototype 2400c/240 (a production 180 with a prototype 240 CPU card). Compare their relative sizes. On top of the bookcase is a TAM (yay, thanks 4seasonphoto!). A working Pippin is on the 2nd shelf next to a "parts" Hooper prototype (603e @ 160MHz, not working). 3rd shelf has a working Assistive Technology Freeastyle tablet, a pair of Wallstreets, a clamshell, a Duo 2300c, and a G3/800 iBook. Bottom shelf has a trio of 3400c PowerBooks, a pair of eMate 300s, another Freestyle, a 1400cs/166, two 5300s, a Duo 280c, a 2400c/180, and a 540c. Some of these are hiding behind my commemorative copy of the University of Arizona's Daily Wildcat from when UofA won the NCAA title.
Other interesting stuff in my collection (not pictured) include a pair of Color Classics and an Apple Set Top Box.
Peace,
Drew