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.
Lenovo Yoga 6 Laptop, 13.3" IPS 60Hz, Ryzen 7 7730U, 16GB, 1TB, Win 11 Home
$714.99
Lenovo ThinkPad T480s Laptop Computer 14" Core i5 8GB RAM 128GB SSD Windows 11
$202.72
Lenovo Yoga 2-in-1 Touch Laptop PC 11.6" Windows 10 4GB RAM 250GB SSD HDMI WiFi
$89.99
Lenovo - Legion Slim 5 16" Gaming Laptop WUXGA - Ryzen 5 7640HS with 16GB Mem...
$799.99
Lenovo Ideapad 1i 15.6" FHD Touch Laptop - Intel Core i3-1215U with 8GB Memor...
$279.99
Lenovo ThinkBook 15 Gen 4 Notebook 15.6" FHD Intel Core i7-1255U 8GB RAM
$619.99
Lenovo ThinkBook 15 Gen 4 Notebook 15.6" FHD AMD R7 5825U 16GB RAM 512GB SSD
$599.99
Lenovo E560 ThinkPad LAPTOP i5-6200U 8gb 500gb NO OS 15.6" 1366x768 20EV002FUS
$87.00
Lenovo IdeaPad Slim 5 16ABR8 Laptop, 16" IPS 60Hz, Ryzen 7 7730U, 16GB
$477.35
Lenovo Thinkpad T470 i7 2.8GHz 8GB RAM 256GB SSD W10 Pro READ
$85.00