Add-on Require Custom User Fields completion for Upgrades

[Mouth]

I'm looking for an Add-On that will make designated Custom User Fields required to be completed as part of the User Upgrade process.

Outcome: When users upgrade to paid members, I would like to capture more information about them. (eg. postal address, phone, etc.)

Setup/Configuration: When creating/editing a User Upgrade within ACP, have a tickbox list (like existing Additional User Groups) of defined Custom User Fields. Tick the box against the Custom User Field that will be displayed/required during the Upgrade Process.

User Workflow: From the Account Upgrades page (/account/upgrades) when a user clicks the Purchase button, instead of being immediately transferred to PayPal, present a page displaying the above ticked Custom User Field(s) for the user to complete. Once completed and the user clicks a 'Submit/Save' button (and standard XF field validation is correct/passed), then transfer the user to PayPal.

Is anyone interested in creating such an Add-On?

 

[Mouth]

Bump. No-one?
If anyone would like to see this too, please reply or like to show potential developers there is (or is not) interest

 

[Digital Doctor]

Require

Similar to this ?
http://xenforo.com/community/threads/profile-completion-steps-paid.33653/

 

[Mouth]

Similar to this ?
http://xenforo.com/community/threads/profile-completion-steps-paid.33653/

Sort of, but not really. The above Add-On is a nag for all users.
My request is for custom user fields to be required for defined upgrades - quite a bit different.

Nb: I already have/use the above add-on too