As a test/proof-of-concept i created a payment page, based on the "Payment request" (bunq.me) functionality.
It shows the bunq QR-code, so people can pay with the bunq app. And it also can generate a iDEAL payment link.
Check this screencast video: https://www.youtube.com/watch?v=aLlP9Nx0WYA
Used API endpoints:
https://api.bunq.com/user/{user}/monetary-account/{account}/request-inquiry
https://api.bunq.me/v1/bunqme-request/{bunqmeGuid}/bunqme-reassign-request-token
https://api.bunq.me/v1/bunqme-request/{bunqmeGuid}/bunqme-reassign-request-token/{token}
https://api.bunq.me/v1/bunqme-merchant-request
https://api.bunq.me/v1/bunqme-merchant-request/{uuid}