Update: Here is a list of Mainboards that work with AthlonXP CPUs, along with a few explanations. The following info is a little outdated, now. It's dated 30.7.2001:

One of the more interesting questions surrounding the future of the A7V mainboard is wether you will be able to upgrade to a new generation Athlon featuring the CPU core code-named "Palomino".

The new BIOSes 1008 (A7V) and 1006 BETA 0.1i both are supposed to support the Palomino. Since AMDs competitor Intel requires new mainboards with almost every new generation of their CPUs, even if they only feature minor changes, it was not too sure that the Palomino would perhaps require new mainboards, or at least new revisions.

Fortunately, AMD seemingly did better than Intel. Both Mainboards tested (A7V Rev. 1.02 and A7V133 1.05) don't have any appearent problems booting with Palomino CPUs.

Working for a few hours with the A7V and a Palomino @ 850Mhz did not show any unstabilities, either.

Since the 1133Mhz Palominos used were not unlocked, there appareantly is an issue with the A7V. To achieve 1133 Mhz, the front side bus (FSB) of 133Mhz is multiplied by 8.5. The A7V only supports 100 Mhz FSB, so the only speed you can get the CPU to work with is 850 Mhz :-(

One could try unlocking the CPU as has been done with countless old Socket-A Athlons, of course. The palomino shown above seems to be quite like the well known Athlons and thus may be unlockable. But the version that will eventually hit the shelves will be quite a bit different. It will feature a brownish plastic instead of the ceramic used nowadays. The little gold bridges will still be present, so hopefully someone will find out how to unlock the palomino.

Update: Unlocking has been found out. See Tom's Hardware for a good explanation

Conclusion

The chances are quite good that using Palomino CPUs in A7V133s will be possible without problems. If the final version will be unlockable, one could also use these CPUs at the speed they are meant to be run at in the A7V "classic". The BIOS should not be the limiting factor ...