Well a lot of games just need the NTSC tooltype added and they will run in NTSC. The really early packs (like the one with the Arkanoid NTSC you mention) are a little out of date now so aren't really MY packs as such.
There are some games (such as Arkanoid) which refuse to run in the different screenmode. I am all for supporting NTSC versions however, if you do find any which refuse to run with the NSTC tooltype then let me know and I will do my best to get an NTSC version in the next pack.
I AM still working on the packs in the background despite not having a site to put them on. In fact I've been doing a LOT on the packs recently so I do hope to have the site back up with LOADS of new stuff before October is finished).
I offer no definites though, something else might crop up