epiphany has one of the shelf. I did developed one without any GL impact few years ago for my previous employer. Used couple of custom record in a parent-child schema - which holds all the data/reference for the original invoices. Then used a saved search and suitelet to generate PDF using Advanced PDF template (xml template saved in file cabinet) for the consolidated invoice. Also referenced back the generated consolidated invoice id to source invoices.

do you know if the epiphany one covers the consolidated invoices with multiple currencies ?

I don't think so. Multi currency would be a nightmare for consolidation - I wont attempt it with a ten foot pole 🤔 http://www.epiphanyinc.net/products/e-consolidated-invoice