The current Armory version cannot parse transactions with inputs directly from mined coins. Maybe you could add that functionality? (For P2Pool payouts, etc.)
Can you clarify the issue? I just stepped through the code in the debugger using an address that receives P2Pool payouts, and at the very least, it seems to be computing "Full", "Spendable" and "Unconfirmed" correctly. But I don't have a wallet to actually display such outputs to see how that information is making it to the user interface.
(1) Are the mined transactions showing up in the ledger?
(2) They should be displayed with a little pickaxe. I assume they're not...?
(3) Do those inputs change the balances shown at the bottom in a way you would expect?
(4) Do you have difficulty spending transactions from wallets that receive mined transactions?
OK, I got a payment from P2Pool.
1. Yes.
2. No pickaxe. On the very left of the ledger, the little rectangle that shows how many confirmations the transaction has received is functioning like it was a normal transaction. (I moused over the transaction and it said that it had only 40 confirmations, yet the box on the left was green with a check mark.) The weird thing is that when I double-clicked or right-clicked the transaction to open the window with the transaction info, Armory crashed (I'm using Windows 7, it said that "Armory has stopped responding, checking for solutions to the problem...
(5 seconds later) Click "Close window" to close the program.") I could double-click the comment field and enter/change the comment just fine without Armory crashing.
3. Yes, at 40 confirmations the P2Pool payout amount was shown as unconfirmed and not spendable.
4. With only 40 confirmations, it would not let me spend coins from that mined payout. ("You just tried to spend 0.0205 BTC, including fee, but you only have 0.00004858 BTC (spendable) in this wallet!")
I also encountered another bug unrelated to mined coins. If you send coins to an address you own (your coins "doing a lap"), with zero confirmations the coins do not show up in your 'Unconfirmed' or 'Maximum Funds' balance (and of course not in your 'Spendable Funds' balance either). (I tested this using coins not from my P2Pool payout, and all of the inputs to the transaction had >6 confirmations.)
I'll edit this post when I receive >120 confirmations on the P2Pool payout transaction, and 1 and >6 confirmations on the test send-coins-to-self transaction.
EDIT: I can open the transaction information for non-mined-coin-input payments just fine.