AR riding eh? Cool. I am actually building a bike that might fit your description as we speak. I chose the CS-MB01 From XMCarbonSpeed. When I was shopping, I wanted a hardtail, but I was looking for something that was a little more forgiving in the rear as I want to run a full carbon seat with no padding and I have an old injury at my L4 disk that I didn't want to aggravate. What gave me the idea to look for something like this was the new BMC Teamlite. It has an elastomer in the seat stays that gives the rear some flex and travel. The CS-MB01 doesn't have this but it does have a couple of kevlar inserts. What they did with the design is decoupled the top of the stays from the lowers by cutting them on a 45 degree angle and then inserting kevlar housed in a flexible casing in between. I don't believe it will give the travel the BMC gives (claimed 12 to 15mm) but I do think it will soften the harshness just a bit. I will find out this weekend when I go for my first trail ride on it.
As for price, I am pretty close to your 3K mark in price as well, maybe just a tad under. Here is what I have:
Frame CS-MB01 - Carbonspeed (Peter @ xmcarbonspeed.com)
Wheels 29 with Novatec hubs - Carbonspeed
Bars - Carbon from Carbonspeed
Seat Post - Carbon from CarbonSpeed
Saddle: G-House all carbon (Selle SMP clone) $25 from Aliexpress (Thanks carbon_dude for the link, I love this thing!)
Fork - Fox 32 Factory SC (Step Cast) very light and got it under $875. Message me for supplier.
Brakes: Hope Tech 3 X2 - Merlin Cycles for about $260.00
Rotors: Hope copies by Snail from AliExpress ($25 for the pair)
Stem: Fun 80mm 7degree from Chain Reaction Cycles (about $25)
Grips: RaceFace Half Nelsons from Chain Reaction Cycles ($20)
Groupset: SRAM GX with 1400 crankset upgrade from r2-bike.com (about $350).
Pedals: I have from another bike.
Tires: Ground Controls 2.3 ($55)
... Just did a running total and I think I'm at $2795. I have a thread up in this forum and will be updating with more details and pictures over the coming days. I'm one of the early builds on this particular frameset, so I feel I need to give as much feedback as possible to help others out. Check there to know more about the build details.
Regardless of what frame and wheels you go with, these component resources should be helpful. Living in Florida, I was surprised that it was cheaper for me to order the majority of my components from UK and Germany for less than I could find anywhere stateside.... Even with shipping. Just a note on r2-bike.com. If you are in a region like me where the VAT tax does not apply, make sure to register on their site. Originally the prices didn't look so good until I registered. Once they had my geographical location, the VAT tax was removed from the pricing. Just an FYI on that one.