Rune page sideboard

What if rune pages had an additional 3 slots per type and 1 quint on the side that you could fill up and makes swaps with in champ select? I find myself deterred to get new champions with different builds because I can't give up a rune page. Examples include having an AP rune page but wishing to swap out wasted MR glyphs when against a Zed. Or having a CDR quint rune page, but not being able to play both Riven and Zac effectively with it.

Maybe having a sideboard could be a progressive upgrade feature of a rune page where you could pay IP to unlock additional slots