Hi Dynamicsboy,
yes, done that, it's an AddOn now, and I have a few more gray hairs ;) If you mean full-fat open items management for G/L accounts with partial application, unapply, and multi-currency capabilities (adjustments, mixed currency application, "exchange trade" application without gains/losses), then yes, that's what Smart IT OpenItems provides. This can be used in the same way and parallel (in the same transaction) to customers/vendors entries applications. If you need more information, please feel free to contact me.
If you only need to apply entries after posting for certain accounts (no partial amounts, no currencies), this functionality is part of the NL and FR localizations of NAV. They are defferent implementations, though.
with best regards
Jens