Here's a good link from Danie Conradie "Using Game Engine Art Tools to Improve Run-Time Streaming in Online Worlds":
https://www.gamedev.net/reference/art/features/MMOStreamArtTools/
The article is framed in terms of MMO games, and how to present a seamless world even when there are various zones and areas, but really this applies to other games with the same goals. I've deliberately avoided this kind of design in SENG; areas are obvious and require the player to load between them, because I didn't want to deal with this kind of issue, but I certainly found the article interesting.
Shamus talks about how standard RPG systems are not well suited to running a modern campaign:
http://www.shamusyoung.com/twentysidedtale/?p=6194
I've considered making a SENG game set in a swashbuckling era with muskets, cannons, and the like, and I thought of the same problems he describes; that hit-point systems just don't make sense for gunplay, but anything else wouldn't be as fun. Ultimately I've postponed the idea because, well, I think people are more interested in traditional high-fantasy games, and I don't mind that kind of game either.
Last, here's an article by John Harris about Skills and Classes in the roguelike game Crawl:
http://www.gamesetwatch.com/2010/01/column_play_crawlapalooza_part.php
Roguelikes do sort of act as an incubation tank for this sort of design. I'm very interested in this sort of thing; I'm particularly proud of the approach I've taken in SENG. In this case, I've never actually tried the game Crawl, so maybe I'll have to go take a look at it and see what I can learn.
Good to know someone did :P