I think you could look to the operative's extra attacks as a general guide. Making unarmed strike work with multi-weapon fighting and granting that as a bonus feat along with the operative's attack progression would be pretty balanced.
I've been toying with translating the Monk/Brawler myself and I am using the Operative and Solarian as the basic template.
So Flurry of Blows would look something like this...
1st level "Flurry of Blows: When making a full attack with unarmed strikes or melee weapons with the Operative property, the Space Monk applies a -3 penalty instead of -4 for the two attacks."
8th level "The Space Monk's Flurry of Blows improves and may now make 3 attacks instead of 2 attacks with unarmed strikes or melee weapons with the Operative property."
13th level "The Space Monk's Flurry of Blows improves again and may now make 4 attacks instead of 3 attacks with unarmed strikes or melee weapons with the Operative property."
The next two tiers of this feature at 8th and 13th inherit the same -3 penalty as outlined at 1st level since I am not explicitly stating the new attacks are made at -5. This implies I am using a 3/4 BAB. If you'd rather have full BAB, then consider changing the extra attacks starting at 8th level to include a -5 penalty depending on what kind of damage dice you're looking at for unarmed striking.
Ki Pool - use resolve. Example use: Once per round, the Space Monk may spend 1 resolve to add an extra melee attack during Flurry of Blows.
Just be very mindful of how much damage 4 or 5 attacks can bring to a target. You'd want to make sure that if the ability is being used with a class that has a lot of advantages out of combat or spells that the end result doesn't exceed a Solarian or Soldier's damage output.