Jamester,

That looks like a fairly nice kit that you built. Do you have any pics of the build and final project? I always like to see how DIY projects come out.

Anyway, I have found two possible options for you. They both are Troels Gravesen's designs from Denmark. He is a very talented designer and has done a great deal of work in helping the DIY community. OK so here are the two different designs:
W1500/97
Ellam d\'Appolito

The W1500/97 uses the exact same drivers as your kit, but it is designed as a mini monitor, which may or may not fit your HT needs.

The Ellam d'Appolito is a MTM design of course but uses a slightly different tweeter. I am not sure that you will be able to notice the difference. Some really picky people think the 9800 is a little more metallic sounding but frankly I don't hear it.

Now there are a couple things to consider with the mini monitor vs. the MTM design. First of all laying an MTM on its side and calling it a center channel has some inherent problems, mostly off axis listening is somewhat degraded as compared to other designs. So if you looking for a rather large sweet spot this is probably not the route for you. However if you just want to hit a one or two chairs (side by side) optimal listening area this will work quite fine.

The down side of a conventional monitor is mostly making room for the cabinet. However this one is only 12" high so that probably won't be a problem. Another draw back for this choice might be that it will be a little thin as compared to your main drivers, i.e. the bias will probably be +3 or 4 DBs to get it to balance again not really a problem unless you like really loud listening. But fear not there is still a solution and it is what I would go with if I had the equipment. You could build two of these monitors and drive them in parallel from a single center channel. You would have to play around with the spacing to get them to voice well, but it certainly would be doable. Also, it would give you a very large sweet spot for your listening area. In order to do this you would need to take the pre-amp output of your center channel and split it to two different amp channels with one driving each speaker.

One other note, if you need surrounds the mini monitors would make excellent surround speakers.

Good Luck and let us know what you decide.