Well here's the full story on how I got started on my Vantage "frontend" project (I say "frontend", but it is really just a graphic vertical menu for launching games. It does not interface with Vantage directly).
About a year ago when I really got interested in this hobby I stumbled across the ArcadeOS site. I was already using MAME32 on an old Dell Optiplex network computer, but I was intrigued by Vantage's extremely low system requirements, so I pulled an old '486 out of storage (I have tons of these as I used to have a storage facility full of discarded computer equipment). I was impressed that most of the games still required throttling for them to run. I had not even built one cabinet yet, but I decided that this would be a great platform to use on my planned basement arcade. I wrote a simple text-based menu so that my young children could easily use the system, without the hassle of working from a command prompt or "complicated" frontend. Also the program had to be small and fast, to work with the older computer. The only problem with the menu was it was horizontal, and the games were vertical (the setup was going into a cocktail cabinet, which I have since built). I always thought that eventually I would create a better menu, vertically-oriented, and with some "pretty" graphics with screenshots (to help my 5-year old who can't read yet identify games) and also I wanted to incorporate some simple features such as a screensaver (the cabinet is on most of the time).
Lately due to an injury I have had time to work on the new and improved "frontend", which I have aptly titled "Advantage" (yes, very original, I know. Sometimes my own creativity just blows my mind). I'm not really an experienced programmer so I don't know how to make it do all kinds of neat stuff like filter and sort roms or interface with the Vantage config files, but it is a huge improvement on my text menu. It runs vertical, it is very fast (loads almost instantly), runs on any computer with a VGA display, runs in DOS, very small (but not small enough to fit on a floppy). In order to keep it fast it is sprite-based (much like the games themselves). However this requires a proprietary binary file format for all the images and screenshots, so that the processor isn't tied up uncompressing graphics. This makes it about 2mb in size.
Although Advantage is being created primarily for myself, I feel that others may like to use it. I have already built in some features such as customizable screensavers, personalized graphics, and several different key control sets (full mappable keys was too much for me. Like I said, I'm not a very experienced programmer).
After reading your insights today regarding Vantage, I think I will make Advantage for Vantage 1.11, to cover all the working roms. Similar to Vantage itself, my frontend will have to be rewritten to incorporate more features and additional roms, perhaps if interest in the project picks up I will devote more time in improving it.