I love mine! I had to come around to it, but after a little time and some comparisons I've come to really love the thing.
It's fast, stable, lightweight, powerful, and the screen actually kicks butt despite the light bleed.
While everyone would love to see ongoing support for this tablet from Toshiba, it is unclear if it will ever see an OS update at this time. (I also read conflicting info online about this.)
I found a dock. It is part number PA5015U-1PAP and works great.
I bought mine on Amazon, but that seller is out of stock on them now and the part number doesn't bring any up there, so you will have to do some diligent searching around to find one.
I would say if you are serious about finding a dock then get on it and find one NOW.
This tablet isn't a big seller at all, so nobody is going to be keeping accessories on their shelves for long.
Just for fun I goggled that part number and almost all the links are sold out. it will be difficult to shop price on them too, so expect a dock to be a little pricey.
Some links I found in stock:
OOPS, make that the ONLY link. "Get it while you can" would apply here.
The case I found for mine is nice, but adds weight and size to the tablet:
Amazon.com: rooCASE Dual-Axis (Black) Leather Folio Case Cover with 23 Adjustable Portrait / Landscape Stand for Toshiba Excite AT305 10.1-Inch Tablet: Computers & Accessories
While it is highly unlikely that we'll see any more official accessories from Toshiba for this tablet, there are plenty of generic cases with keyboards built into them out there for 10-inch tablets right now. Some are better than others, so it's a good idea to shop around, use a seller that accepts returns and read reviews if any are available.
Personally I'm using the Logitech Bluetooth Keyboard which I have found to be really great.
I've also used mine with a bluetooth mouse, speakers, and a game controller.
The Xbox 360 wireless controller also works if you use the USB dongle for it.
It is also difficult to find much activity on forums online, so I try to cover this one and the Excite section over on the thrive forums too.
(sorry if it is a no-no to discuss other forums, but owners of this tablet don't have many places to go, and IMO deserve all the help and community support they can get.)