Here's my bowl scheme, for a near-future P4 scenario. There are 32 bowls for 64 participants, roughly half of the total FBS teams, plus the extra CFP championship game. Each P4 conference is guaranteed at least 8 bowl games and each non-P4 conference is guaranteed at least 4 (2 of which are against P4 teams).
NY6 bowl participants rotate in a three-year cycle. For example, in Year 1, the Rose Bowl serves as the CFP semifinal between the B10 and PAC champs. In Year 2, it's a non-CFP game between the #2 teams in the B10 and PAC. And in Year 3, it's a non-CFP game between at-large teams. The top FBS team outside the P4 is guaranteed an at-large spot.
Code:
NY6 BOWLS
Peach ACC vs. SEC
Rose B10 vs. PAC
Orange ACC vs. B10
Cotton PAC vs. SEC
Fiesta ACC vs. PAC
Sugar B10 vs. SEC
P4-ONLY BOWLS
Hall of Fame (Tampa) ACC vs. B10
Holiday (San Diego) ACC vs. PAC
Citrus (Orlando) ACC vs. SEC
Alamo (San Antonio) B10 vs. PAC
Music City (Nashville) B10 vs. SEC
Texas (Houston) PAC vs. SEC
P4 vs. NON-P4 BOWLS
Military (Annapolis) ACC vs. USA
Pinstripe (New York) ACC vs. MAC
Birmingham ACC vs. SBC
Queen City (Charlotte) B10 vs. AAC
Motor City (Detroit) B10 vs. MAC
Cactus* (Tucson) B10 vs. MWC
Las Vegas PAC vs. AAC
Sun (El Paso) PAC vs. B12
Santa Clara PAC vs. MWC
Liberty (Memphis) SEC vs. B12
Gator (Jacksonville) SEC vs. USA
Mobile SEC vs. SBC
Austin** at-large P4 vs. at-large non-P4
NON-P4 BOWLS
Independence (Shreveport) AAC vs. USA
Boise AAC vs. MWC
Camellia (Montgomery) B12 vs. MAC
Hawaii B12 vs. MWC
Medal of Honor** USA vs. SBC
New Mexico (Albuquerque) MAC vs. SBC
Bahamas 2 at-large non-P4 teams
I tried to maintain a similar ratio of power to non-power participants as there is currently. Realistically, only one non-P4 team is likely to make the NY6. So this means that in most years there would be 36 P4 spots (56%) and 28 non-P4 spots (44%) out of the total 64. This is comparable to the distribution in the 2017-18 bowl season, where P5 teams (+ ND) have 45 spots (58%) and G5 teams (+ Army) have 33 spots (42%) out of the total 78.
* I moved the Cactus Bowl back to Tucson to replace the Arizona Bowl. Note that no metro areas have more than one bowl. Spread the love, I say.
** The Medal of Honor (Charleston, SC) and Austin Bowls have actually been proposed.