I've just recently come into possesion of a USA Kilt Gordon Modern Philabeg and am in the same boat as you Galant of trying to pick some choice accessories to go with it as well as with my UK Survival. I just placed an order for the Rob Roy from USA this week and am hoping to see it this weekend or early next week.

I'm following Hamish's tips about a simple belt from walmart 1 brown and 1 black for $11.00 / each. They have a slightly pebbled look and texture and are 1.75" wide so I think they look well proportioned with the lower riding casual kilts.

I'm very interested in the belts at this site as a variant of the kilt belt.
https://www.paradestore.com/main_frame.asp
They are not as large but could add a nice touch. I have my Brass buckle and white web belt from my dress blues but would like to replace that brass with nickle. The store also said that August 1st they would be adding some other belts and buckles to their line so I'll be checking back.

I'm probably going to go with a few pair of soccer socks for now in black and/or green.

I'm keeping my eye open for an old mess jacket style to wear for formal occasions but that's a low priority now. A thread here mentioned old rental tux jackets can fill this bill for about $40.00 then just replace the buttons.

The Sgian Dubh is an accessory I like but am usually not in a place where it would be appropriate to wear the blade. I had found a site with very nice antler sgian dubh's at a good price but seem to have lost it.

Bottom line, I agree with you that with one or two kilts and some sensible accessories you can have a great wardrobe...If you try to at least reference Hamish's advise ;)