Jeffsy 29 had a 44mm fork in 2017--it's on the Fox-equipped bikes now. I don't think they market it at all. For aggressive cornering, it's better, due to relative ease of countersteering. Shorter stems and bigger wheels make it all the more desireable. Is it worth buying a new CSU? No. Is it worth looking for if buying a new fork or bike anyway? Yes. Fox has had 44 and 51mm options on 32 Float 29s for at least a couple of years now. Don't be surprised if all the 29" forks are 44mm soon enough.
Agreed. Overly slack actual seat tube angles may introduce insurmountable weighting problems, as many angry commenters have remarked, sometimes in conjunction with the accusation that manufacturers are misrepresenting toptube lengths. I see Knolly has not provided an ASTA for geo of Fugitive. Judging from their 'technical data sheets,' Bird looks to have it better sorted.
What if we change the designation from actual seat tube angle to seatpost angle? The closer the seatpost angle is to the ESTA, the more meaningful the ETT. Taking crude measures from a 5010, I estimate that for every cm of saddle height above the horizontal ETT line, the actual top tube--measured from center top of head tube to seatpost axis atop saddle--increases about 4mm. I can see why manufacturers don't want to get involved in providing charts on this, but it's not that complicated to observe that the difference between seatpost and effective seat tube angle is more pronounced on a Warden than on a Meta 4.2, for example.