I think the A series could handle a wet sleeve conversion. The legendary Honda H22 is usually converted to a wet sleeve and its an alloy block which handles ridiculous boost. Once you have good seating on billet sleeves the head seals the lot specially with stronger head bolts (somewhere on this forum I saw someone using the stronger bolts). The problem is finding someone to do an accurate job of CNCing the block for the stronger sleeves.
Smaller 75mm bores will make 1431cc but will help with thicker billet sleeves which is necessary for 40-50psi.
Billet Stainless sleeves will cause problems to the rings but coating the rings will help with them disappearing.

One other thing is that the 82mm stroke is not an issue with revs. The H22 has a 90mm stroke and revs to 9k with boost and the F20/22 rev to 9k with 86mm stroke.
With boost 82mm should be fine on the A series for 7.5k easily