I am fairly sure I can adapt a UK instrument cluster to pick up a speedo signal from the ABS system, but I have not yet tried it because there has, so far, been no need. I'm not sure whether I'll be able to do the same for left-hand-drive A2s, as I have not yet had the opportunity to learn. If you need to have your instrument cluster adapted in this way, I will be more than happy to help, but I would not want you to drive here from Denmark before I am sure I can solve the problem.
I've done some more investigation into this matter. My new understanding is that the software inside the instrument cluster is totally irrelevant when it comes to speedo signals. All instrument clusters pick up a pulse-based speedo signal; earlier clusters use the gearbox as the source, whilst later clusters use the ABS unit as the source.
If you fit a gearbox without a speedo drive (such as the 6-speed MYP gearbox), the cluster must then be able to pick up its speed signal from the ABS unit. However, if the ABS unit doesn't have a speed signal output, you've got serious problems!
My current belief is that the earlier MK20 ABS unit doesn't have a pulse-based speedo output, which would explain why it's fitted in conjunction with a gearbox speedo drive. Based on this new understanding, the 6-speed upgrade method suitable for a given car is therefore determined by the generation of ABS unit fitted, not the generation of instrument cluster. If you've got a MK20 ABS unit, you must upgrade via a gearbox extension (such as the one fitted to my car: http://www.a2oc.net/forum/showthread.php?21523). If you've got the later MK60 ABS unit, both upgrade methods are available to you (either MYP 'box or an extension of your existing 'box).
If the MYP gearbox can have a speedo drive retrofitted, then the MYP gearbox option becomes available to all 1.4 TDIs. However, this would require investigation and may be physically impossible or prohibitively expensive to realise.