I had the stray interrupt problem last week and determined a solution on one 
particular machine.  Some facts:

(1) The lpt driver needs to be in the kernel.

(2) Some systems have LPT1 at 0x3bc (the old IBM mono/printer adapter
address).  Either tell the kernel the right address or tell the system to
use LPT2 instead.  I opted for the latter, since it didn't require a 
kernel recompile.

(3) Disabling the port didn't make one whit of difference.

As far as using two IDE drives, I had that problem with 1.0alpha, but 
never had need to try it after that.  Perhaps you might try it after 
solving the stray interrupt problem, again.

--scott