I did, but did you happen to see where I wrote...
[color=#0000CC]"Perhaps somewhere in the recent panel maintenance some old code was reintroduced that also re-instated this restriction."[/color]
I don't think it is the promo-code(s) that you are trying to use that are causing the problem, I think it is the DreamHost automated fraud detection system.
I just tried a test sign-up using my own promo-code with pseudo-random entries for name/address etc. and sure enough I saw the 'credit-card only with promo-code' message that you saw, I was also restricted to Google Checkout or mail-in check/money order for payment.
I then proceeded to try another sign-up, again using my promo-code, but this time I used a legitimate name/address etc (Australian address). This time I did not see the 'credit-card only with promo-code' message and I was also offered the full range of payment options.
From the above, I can only assume that those unlucky enough to trigger the fraud detection system (for whatever reason) and are offered only the Google Checkout option for payment, will also see the 'credit-card only with promo-code' message. I think this is regardless of what promo-code you use.
Save [color=#CC0000]$50[/color] on DreamHost plans using [color=#CC0000]PRICESLASH[/color] promo code (Click for DreamHost promo code details)