Is there a Cisco box (switch maybe) where E1 (with the suitable SFP) can be plugged-in, so that Ethernet data can be transported over E1?
Note that I am aiming a Ethernet-only solution rather than connecting two routers with E1s.
You will find that there is no SFP for E1.
E1 is an electrical interface and if you want to tranport ethernet over if you can use bridges like blackbox and others.
At which point you will find that two routers may be similarly priced, and allow a better use of bandwidth.