Thats odd, i have a load of pint glasses. Most of them are Guinness from Carrolls. I also have an Amstel one i got free with some cans <!-- s:D --><img src="{SMILIES_PATH}/icon_biggrin.gif" alt="

" title="Very Happy" /><!-- s:D --> I also have a Lord of the rings pint glass.
I have also got two Guinness brewhouse series glasses i had swiped for me by my wife's lovely cousins. They put them in their handbags (only use for them).
Now i have never been able to fill an Irish pint glass to the top with 500ml bottles or cans. There is always plenty of room left.
On the other hand, i got a 500ml Guinness glass free with a Guinness promotion they send out to me all the time. Its designed for their draught can of Guinness. I find that one holds exactly 500ml but with the head on the Guinness it can start to overflow.