Probably not something that Team Ulysses would consider adding to ULX, but an interesting idea nonetheless. Patreon does provide webhooks when someone creates or deletes their pledge, so this is theoretically possible. However you would have to somehow link their Steam account with their Patreon pledge, so it wouldn't be entirely automatic. Patreon does support OAuth, so I guess you could have a website where they log in with Patreon and supply their SteamID or log in with Steam OpenID.