Knoppix may be run with several desktops, and GNOME and KDE can be chosen with the desktop cheatcode. After the introduction of LXDE, there does, however not seem to be so much interest in other lightweight alternatives.
What about using Enlightenment and the EFL (Enlightenment Foundation Libraries)? This is used in a Ubuntu derivative called Bodhi Linux, and some users seem to be very content - it's seemingly not the best for newbies, though.
What makes Enlightenment particularly interesting to me, is that it is the preferred desktop alternative for the Tizen project for full-version Linux on mobile devices (as opposed to the kernel+Android stack approach) This is Debian-based, and shouldn't really be that far from Knoppix, porting Knoppix to mobile devices should become easier with every day now.
Using Enlightenment with Knoppix could provide one of the stepping stones to mobile Knoppix, or is this approach futile?
Without having asked about this, I guess KK's first answer will be negative. Knoppix is extremely hardware agnostic, but achieves that by sticking to hardware based on x86 architectures, and keeps the 32-bits approach. Not even a 64-bits version is in sight (if things haven't changed lately), and I have come to support his approach, IMHO it's very practical to chroot into a 64-bits system from hybrid Knoppix and doing everything purely 64 bits there.
This 32/64-bits situation will relatively soon be parallelled in the mobile scene, making the whole situation even more convoluted.
It will be very interesting to see how the Tizen project develops - but there will actually be several Debian-based mobile alternatives. A Ubuntu version was recently announced, and you can already download an alpha release of Bodhi for the Asus Nexus 7 tablet. The Knoppix take on this might be to adapt a minirt.gz for mobile devices, which I guess will have to be tweaked separately for each new device in the first place.
With 2-4GB of RAM and 16-32GB of internal storage on the upcoming devices, there should be room for a Knoppix compressed image+persistent store without wiping out anything else, setting up for multi-boot.
Atari 600 XL Vintage Home Computer - New in Box, Unused
$200.00
Vintage Atari 800XL Computer With Original Box
$140.00
Vintage Family owned Atari 1200xl computer sold as is tested turns on with cable
$299.99
Atari Power Cube 800XL, 600XL, 65XE, 130XE USB-C Power Supply PSU
$11.25
A8picoCart Atari 130 / 65 XE 800 / 1200 XL XEGS multicart UnoCart clone game
$32.95
Vintage Atari 800XL ~ Home Computer in Original Box ~ Tested and Working
$149.90
RARE San Jose Computer Special Edition 810 5 1/4" Floppy Disc Drive Atari 8-bit
$195.00
Atari 520 1040 ST Astra Systems 4 Meg Computer Memory Card 4MB
$59.00
Ms. Pac-Man Game Cartridge Atari TI99/4A TI-99/4A 1983 MS PACMAN UNTESTED/AS IS
$21.24
$225.00