I, for one, don't see "hose, flashes and sporran" as incompatible with casual kilting. One can wear all those things and still be in casual dress. In fact, I consider what I have on today -- polo shirt, kilt, brown leather belt, brown leather sporran, hose & garters, brown leather shoes -- to be a rather generic "casual" kilting outfit.

You need a sporran to keep your goodies about you because (with the exception of some contemporary styles) kilts are sans pockets!

You need garters to keep your hose from slipping. And while you don't strictly need hose, it is part of the "Highland dress" style to wear kilt hose with the kilt.

Now, if you want to substitute hose and garters with boots and socks, that's fine. It's a valid contemporary style. But I still think some kind of sporran is in order. To me and many others, the kilt just looks "naked" without a sporran. Plus it is functional.

Bear in mind there is a wide range of sporrans, from very simple to very extravagant, so perhaps you can find a simple, functional style that you like.