If you haven't seen Alexander Rogals outstanding OH-58D build you should definitely check it out: http://www.arcforums.com/forums/air/index.php?showtopic=227564
Many of those parts are now available (as well as a few that I made) with a bunch of photo-etch details:
More details and some better pics can be seen in the ZactoForum: http://www.arcforums.com/forums/air/index.php?showtopic=233605
Already ordered the MMS and want the rest? E-mail for details. Zactoman@Zactomodels.com
The set is available at http://zactomodels.com/
Cheers! Chris