There's a horrible, HORRIBLE variant for Samurai to pay XP instead of making wealth sacrifices to the ancestors, in the Rokugan book by AEG.
I say it's HORRIBLE because it's HORRIBLY BROKEN. You pay a
piddly amount of XP for the daisho enhancements with that variant. It's absurd.
This is the compromise version I came up with for a player in my Rhunaria campaign. I don't think merely sacrificing XP would be quite appropriate anyway for the way the Samurai is written, but I dunno. You have to respect the ancestors, yo!
And that means taking care of the family shrines sometimes.
Minimum...........Total........Total GP..............Total
Samurai.............XP..........Value Of..........Enhancement
Class Level.......Cost........Sacrifices...........Equivalent
4th...................60.............750...................+1
7th...................240...........3,000................+2
9th...................480...........6,750................+3
11th.................960...........12,000...............+4
13th.................1,500........18,750...............+5
14th.................2,160........27,000...............+6*
15th.................3,090........36,750...............+7*
16th.................3,840........48,000...............+8*
17th.................4,860........60,750...............+9*
18th.................6,000........75,000...............+10*
*Actual enhancement bonus cannot exceed +5
And I was probably still too generous in lowering the GP cost for the amount of XP cost I required. But Rhunaria has less wealth than standard settings, which I think is the only reason I didn't increase the costs a bit beyond this.