My name is Kevin and I've recently purchased a few PCjrs to cobble together a tricked-out system (and, in the process, to relive my childhood...)
I got my original PCjr, a 128K "enhanced" system, back in about '86 (I was 7 years old): my dad worked for IBM at the time and I think he got a real good deal on the system since they were discontinuing it and all... It had the better keyboard (non-chicklet), the IBM color display, 128K RAM, and the single 5.25" 360KB floppy. My favorite titles as a kid were King's Quest, Monster Math, and Gertrude's Secrets. Soon enough, however, the black power brick burnt-out or something, and in '88 or so, when I brought it to my local PC-repair shop, they laughed at the idea of repairing it (and in the process sold my mom a Leading Edge Model D, which was to become my base system for the next several years). Thus, the PCjr got pitched to the trash, though I did keep several diskettes for nostalgia's sake...
Some of which *actually worked* when I regained an interest in the PCjr about a month ago! I hadn't booted off that IBM DOS 2.11 diskette in nearly 20 years! Now *that's* a quality product!
My PCjr Redux system has 128K on-board with a 512K aftermarket daughter board between the CPU socket and the 8088 (it just barely fits beneath the floppy), for a total of 640K RAM. The floppy is interesting - it's not the typical black drive with "IBM" cast into the plastic (though I have some of those too), but rather a YE-Data 360 KB floppy, grey/beige in color, with an asterisk cast into the front plate: it looks kind of like the 1.2 MB drives that came with the IBM AT (I had one of those too, once upon a time), and it has an IBM replacement part number label. I'm wondering if it wasn't an "official" IBM replacement for the original black-plastic floppy (which I'm made to understand weren't very good drives), though it could have just been installed from anywhere, I'm sure.
I have some sidecars which are intended for, but are not currently in use on, the system: (2) IBM 128 K RAM expansion sidecars, an IBM parallel port sidecar, an IBM power booster sidecar, and a Microsoft PCjrBooster w/. RAM, clock, and (bus?) mouse port (I also have the mouse, which appears to be in pristine condition).
I have a few things I want to do to this system. Firstly, a buddy of mine is handy with the soldering iron, and we just did the "Tandy mod" (to get rid of the black horizontal lines in Tandy 16-color graphics mode) to one of the spare motherboards and it worked! (Next to apply the mod to my current system, though we're going to have to get more creative with chip-placement due to the space taken up by that RAM daughterboard...)
Secondly, I really, really, really want 736K addressable by DOS. If anyone knows how to do this, advice would be greatly appreciated!
Thirdly, I want to get the PCjr on the network (I've already ordered some of the Xircom parallel port ethernet adapters) for use as a text-based terminal to access apps on some Linux boxes I've got running.
Fourthly (and finally?), I want to have a hard drive on the machine. I know there were some hard drive housings that were chassis expansions, but that these are rare as hens' teeth. Alternately, I'm imagining a parallel port hard drive, though I'd need another parallel port sidecar (they seem reasonably available) and I'm guessing it'd have to be modded to appear as LPT2 and take up another IRQ (I'm made to understand IRQs are weird on the PCjr, as compared with the PC).
So yeah, I've typed way too much, and I'll try to keep my questions to discreet topics on the forum. But that's my system. Oh - and about me? I started repairing PCs when I was 14, and did hardware and software support for 15 years. Then I decided I was tired of "IT" and am now working in the medical transcription field (but as a user
). I'm an avid reader of non-fiction ancient history (studied Latin and Ancient History at college), player of Oblivion and Fallout 3, like long walks on the beach at sunset (OK, not really - I hate the beach). 
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