I was looking for pictures, when I found this and a link to another GW post. Hope this helps :)
{{gwi:1411584}}From Stairs, landing, entry, etc.

Here is a link that might be useful: Link to transom thread

I'm not quite sure I understand your problem with different heights, but it's early so maybe my math brain isn't working. Exterior windows top out at 8 feet. Interior doors at 6'8" plus a 16" transom also equals 8 feet? Perhaps your architect is worried about the trim around the doors? It would seem like there should be plenty of space above for trimwork.

As far as sources: any trim carpenter should be able to build these onsite with common lumber, trim, and glass. That old thread linked above gives a brief description of how it's done.

LL: love that pic! I wish we could have transoms above all the windows too... but alas only inside. But I think I will paint a room blue, just like that one.

rrah: Ha. My math brain is never working, but you were right. Yes. It adds up theoretically but only if there is no trim or wood between the two (door and transom) for the interior parts, because the windows will just be simple double hung up to the 8 foot mark. I'm not sure how that's done or measured, so I hoped someone had a picture with directions so I could explain it properly. Apparently not too many people do interior transoms around here. But... if they can build it on site like you described, it should work out fine. I hadn't thought about that option. I was having window companies price it out!

We have a number of interior transoms. Ours are all old British glass and we had them made wider to match the doors. Then the trim carpenters framed around them.

dekeoboe: Oh. My. Goodness Gracious. Those transoms. Those doors. It looks like a verifiable "old house." I love what you did!