Hi and welcome amcmerino,
Sorry we currently do not have any dropshippers based in Spain. I have tried searching outside of SaleHoo for previous requests, unfortunately I have not found any at all. But we do have a number of dropshippers who will readily ship to Spain and most other countries worldwide.
Here's a link to a previous post with dropshippers that may offer free shipping - Link hidden: Login to view
Remember that wholesale price is very dependent on the volume of your orders. So if you want lower and more competitive prices then you will need to make a bulk purchase which is very seldom done when sourcing from dropshippers.
I highly doubt eBay sellers will share the suppliers they are using, as much as possible online sellers will do their best to conceal their suppliers to protect their business. Sorry I cannot say if the suppliers in the link above are commonly used by eBay sellers but I know for sure that they have been pre-screened by SaleHoo to ensure that these suppliers are legit and safe to use.
Hope this helps :)