http://www.fanfiction.net/s/9393611/1/Steadfast
I'm still planning on reading In Flight to the end, but this fanfic of In Flight, perhaps the only one I've picked up and intend to read to its conclusion, feels so far like In Flight did before I started losing interest; most of the good stuff without as much of the bad. Don't think it's been recced here yet.
Basically, it deviates from when Rin and Saber arrive at Miya's Inn. The description reads: An alternate universe of Gabriel Blessing's In Flight. "We promised to stand beside you. Do not push us away now." [Diverges after chapter 38, Rin, Saber, Shirou centric.]
The authors' note at the beginning of the fic warns that the authors (looks like it's a co-authorship,) intend to continue the slice-of-life with intermittent battles aspect of In Flight. The only real problem, though I haven't noticed anything wrong so far, is that the author(s) have professed to have no familiarity with Sekerei beyond In Flight. They note in author notes in later chapters that they've been consulting the manga, but I dunno if they're actually reading it. They also later admit that just about everything after their divergence point from In Flight is being discarded. So far, I have to admit I'm liking this fanfic of In Flight better than the original fic after the divergence. The idea that Shirou as characterized in In Flight itself and FSN could abandon people he felt that strongly about when they are not in agreement with said abandonment... it just doesn't sit well.