Hey Doc! Haven't bumped into you in quite a while. Unfortunately I'm afraid you're right. The 6000 specific parts are DEFINITELY becoming scarce. However having said that you're not completely out of luck....yet.
You can still get the sled from conics.net. The battery I'm not sure about. You CAN still buy it. It's expensive at $248, I bought mine at the time they were selling brown box specials at Amazon and paid $170 I think.
Here's a link- http://www.conics.net/catalog/product_info...&products_id=88
I googled for the battery about a week ago and came up with several "in stock" hits. Seems like the cheapest was $80-85ish.
Expensive stuff, but if you already have a 6k of any flavor, NOW is probably the last chance you're going to have to step up to the table.
I think the release of the C3100 if anything has underscored the incredible value of the SL-6000 product line. It has taken over a YEAR AND A HALF for Sharp Japan to produce a product that is equal to or greater than the features we have enjoyed daily during that time from SharpUSA's 6000 series. I paid less than $400-500 for my 6000's (We have 3 in our household). I paid about $170 for a exp sled for mine, and recently a friend bought me a 4gb Hitachi Microdrive from Newegg on sale for $107. The same friend is handling having one of my 6000's upgraded with the Bluetooth hack to give it 6000W functionality at a total cost of about $38. (I have NO clue where he got the chip or who's doing the soldering- He's in the industry and he's pulled off similar miracles for me before.) So all told I've got between 700-800 bucks invested (minus the bazillion peripherals that are useable with any pda).
Over a year since I initially bought mine and you STILL can't get a C3100 with similar performance and options. Using BT, WiFi, USB host, and filling one of my two CF slots with the microdrive STILL leaves me with an open SDcard slot and an open CF card slot. (The 3100 in the same configuration can't give you that since it must use the CF or SD slot to house bluetooth cards etc.) I suppose if the 3100 line integrated BT into the offering it would balance the scales.
At this point the only things the C3100 has over the 6KW (or even L) is the clamshell design if you prefer that function, and the SD card being an I/O slot. Oh and the USB Host/Client is 2.0 but while I was annoyed originally when I opened my box and found the Host only complied with USB 1.1 I really have never found a usage that made the slower USB port annoying. I suppose you could also use the argument that since it is built on the C860 platform that it will be more compatible with the differing ROM offerings. So far the C3100 hasn't reached the compatibility level of the 6000 but it surely will exceed it eventually.
If the 6000 had never been released I would have pre-ordered a C3100 the day it first became available, but after using and loving my 6k for a year+, I couldn't honestly recommend to anyone that is already a 6k owner to "laterally upgrade" to a C3100. It makes MUCH more sense to grab a sled and possibly do the bluetooth hack and hang in there for another year... or however long it takes them to produce a REAL SL-6000 killer.