Please post some of your Error-Messages or the whole "Boot-process" so that we can find out which problems your plug has.

You could try to use another USB-cable, because not every mini-usb-cable does work properly because of the
poor connection to the usb-port. You could also tryto put the sheeva on her side to ensure the connector does insert from
the upper to the lowerin the usb-mini-port.

Is the USB recognized? Did you use another USB-Port on your Laptop/computer? On a other USB-Port Windows will install an additional virtual com-Port with another Number (COM1: -> COM2:)

No chance :-) they did not got a x86 CPU.
debian and Android is available :-)

at the details page I did only see:
US Model -           Price $149.00 (USD)    and
US Model + JTAG - Price $179.00 (USD)

BTW: I would like to see/hear about: "We have a small robust product which draws under 5 watts of power"

but then the device and the cables/connectors should be more stable.
On the Guruplug (plus) I wouldnt connect/disconnect the cables to much times...it seems to be only
a one time connect for developers.

I personally did got problems with a (Micro)SD Slot - and this one will not be changed/switched very often.

I read many onboard flash problems, but with the Seagate Dockstar.
There is a special programm needed to go around the errors in the flash chip which has "bad sectors"/cells

I couldnt see the same Ports as on the Guruplug (for JTAG/RS232)...
and my opinion would be that a "Dream Plug" has to be like the Sheevaplug - with a included JTAG/RS232-USB-Port

Whats the problem with internal MicroSD in your opinion?
From my point of view its seems to be better...
- you could swap it if it get faulty
- you could reprogram it externally it the content goes bad (no need for a jtag)
- you could upgrade(?) the size

And the big question is: Will it run quite cool on Gigabit-Ethernet usage?
The detachable power-supply is a fine idea :-)
It would be cool getting a base-stand like on the PogoPlug if the original power-supply is detached- for a even better airflow?
I also like to get back the SD-Support against the MicroSD :-) 

Yes, you could connect the red wired to plus and the black wires to black/ground.
The power-supply you did remove from your sheeva seems to a the newer improved
version which shouldnt smell/burn....but your one did fail....the older ones did fail after
a they burn and smell.

If you search on eBay for "Bluetooth ttl" you will find low priced Modules (2 pieces around 15-18EUR)
which convert TTL-RS232 3.3V to Bluetooth.
The modules can be configured as Master or Slave and the Baudrate could be set.
So its possible to create a Bluetooth-Serial-Console for and possible inside a Dockstar.

If the Modul is configured you have only to connect 4 wires (3.3V, GND, TX and RX)

A picture of the module can be found as attachment

sorry only 1x GBit Lan

but at a "high" price of 89EUR
http://www.synology.com/deu/products/USBStation2/index.php

800Mhz Marvel 6180 - http://www.marvell.com/products/processors/embedded/kirkwood/88F6180-003_ver1.pdf
+ 128MB Ram
+ 2x USB
+ 2x GBit Lan
+ no HDD
+ nice Case but round Top-Case
+ supports music, Internet radio stations, and iPod playback with the optional speakers
+ An optional direction-free Synology Remote allows you to freely enjoy your music

High price because the Seagate Freeagent GoFlex Home with 1TB Harddisc sell for about 114EUR

How about Plug Computer 2.0 for 2011? The GuruPlug Plus wasnt a 2.0....mostly only a 1 3/8 :-)
Nice try, but a retry would be nice.... my GuruPlug Plug is waiting offline beside my Sheevaplug and Dockstar
for a new case.

Do you think thats the software issue (bad driver) of the client mode like in the following thread?:
http://www.newit.co.uk/forum/index.php/topic,455.msg3208.html#msg3208