Well, here's the scoop so far on what I saw in Akihabara today:
-I didn't see a Saturn Twin Stick, but I did see a Dreamcast one. Forgot to check the price. Big box.
-PC Engine, around 2000 yen. Cheap.
-PC Core Grafx. Forgot to check the price, but it was out of the box. Probably cheap.
-PC Engine Duo - not quite what you were looking for, but maybe it'll do? Unfortunately, it's 14600 yen. At the current exchange rate, that's about $170USD. I did see a PCFX, however. Don't know if it's compatible, but it was only 5700 yen.
-Saturn Memory carts around 1500 yen.
-Resident Evil Veronica Dreamcast system for 38800 yen. Ouch.
-Mega Adaptor (insert Master System carts into a Mega Drive model 1 but I don't know the compatibility with systems/games from other regions), 6000 yen.
I didn't see Doom while I was browsing, but I bet if I ask around, someone will have it. Unfortunately, I still haven't figured out how the Japanese organize stuff, so unless something catches my eye while I'm browsing or I specifically ask, it's hard for me to find specific titles. Didn't see Bomberman, either, but I'll ask around tomorrow when I'm not juggling so many things in my head or in my hands.
There were SO MANY different games for different systems at some of those stores. I wish I'd had more time, but as I said, I was carrying way too much in my head and in my hands. I made a note of the names of a few of them. Trader was a big one, and Retro Game was small but packed. I still haven't found Super Potato, which is another huge retro game store that my friends recommended. Hopefully they can show me where it is tomorrow.
I snatched up a bunch of Super Famicom games on the cheap as well as another controller and power supply for it. I may swing back and pick up Metal Wolf Chaos for the Xbox, which is something like 7600 yen. It's the one Xbox ISO I still have that I haven't replaced with a physical copy, only because you CAN'T FIND THE DARN THING as it only came out in Japan and no one seems to sell it on eBay. Scratch that - It is sold on eBay now... for almost 1.5 - 2x what I saw it for at Traders. Also, while I was grabbing Super Famicom stuff, I just happened to see a loose Saturn Twin Operator RG-VC2 on sale for a mere 1200 yen at Retro Game, which I quickly snapped up. I just looked up the guides I referenced back when I hunted down my RG-VC20 for more than that on eBay a while back... it's only an NTSC MPEG decoder (no PAL), and it says on the card itself that it will play PhotoCDs (although one of the guides disagrees with this... testing will be required when I get home). Still, great find! I'm excited to go hunting again tomorrow!
If you guys seriously want me to grab any of this stuff or any specific games, you need to let me know by maybe 9PM EST. It's going to be a challenge to fit more than one system in my luggage, though, and I wouldn't be surprised if I get charged some kind of import tax when bringing it back into the US. Be sure that it's something you are willing to and capable of paying for. I don't want to bring home a bunch of stuff that I don't really want. If it's not something I listed, let me know what you're willing to pay, and I can see if I can find it for that price, otherwise I won't pick it up. That PC Engine Duo is probably the most expensive item I could swing right now. That Res Evil DC is right out. If it's too big, I may have to ship it home, which will get expensive. :/ I won't charge you guys anything extra over the cost of purchasing it and any shipping costs.
Also note - all those system prices were in-box. I didn't see any out of their boxes, but they might be less if I can find one. As I said, hopefully I'll be able to hit up Super Potato tomorrow and see what they have, as well as the shops I visited today.
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I can't make any guarantees that I can grab this stuff - but I can try. If you're serious about buying something, just let me know what you're willing to pay before about 9PM EST (Yes, 9PM. That's 10AM here in Tokyo.) so I can make a list before I go shopping tomorrow. 10AM is an estimated departure time for me. If I don't see your message before I leave, I may not get a chance to look for whatever it is you want. Don't forget to consider shipping costs. Games are cheap to ship, but systems or large peripherals are not. :/ I'll try to be fair with what requests I can fulfill and which I can't, but if I have to, I'll resort to post order, starting after this post.
Bleh, I didn't want this post to end up with such a serious mood, but... *shrugs*