I want to use Stripe with a multi-vendor Magento store, where a charge would be split between the main Stripe/store account and a vendor accounts?

Is there any current support (or maybe planned for future versions) for Stripe managed accounts - for use with multi-vendor Magento store, where charge would be split between main Stripe/store account and vendor accounts?

Also is any support available for modification of your extension, for example to cover mentioned managed accounts functionality?

Thanks.

There is no such support yet.
Use the customization service to order a modification.