The closest in the US to the Shadows was the Ventures. But don't get too hung up on the name, think any early Strat players from Buddy Holly on and you have the clean sound capability, only better.
To understand Hank Marvin and the Shadows (or any defining players, Clapton, Hendrix, etc), you really had to be around at the time, late 50's early 60's. Compared to what was available before, the Shadows stuff was new and exciting and Hank is named as a seminal influence by virtually every guitarist who was around at the time, and who was enthused to take up guitar by him (that includes me!). Yes things moved on, and by the mid 60's, they were old hat. I recently saw Hank play at the Strat Concert at Wembley and he's still a very good guitarist indeed. Unfortunately (or fortunately!) nowadays any 13 year old has access to equipment of a quality we only dreamed of, can have lessons, and in no time can play any Hendrix riff you might wish. We had to learn them from the record, with no clue what the man was doing!! That is when you really appreciate people's inventive play. When I was a boy 'widdle' was something you did at the urinal :o