I love the pic too!
I'm in a LDR. 3 years this February. The difference is that (finally!) it will all be over in March. I'm moving to CA to be with him then.
But, I know how hard it can be. I am never, ever doing the LDR thing again. Once I'm with him in person - he's mine. All mine. ::insert evil laugh here::
Anyway, what I used to do a lot is make him small things he could open each day. That way I was (kind of) always there. For instance, for xmas, I made him 96 felt fortune cookies with little notes in them. (I also have no life.)
For Valentine's (since he always says I'm too much of an introvert and need to be more open) I got lots of walnuts. Cracked the shells, neatly in half. Took out the nuts. Put a little note in each nut. Sealed it with hot glue. The notes were all about me - what I"m thinking, feeling, etc. In the card, I wrote "I know I'm a hard nut to crack, so I thought these would help you out."
Yea, I know, cheesy. But, he digs cheesy.
Other than that, someone posted a thread on here about the mini origami stars. I thought that was a neat idea.
I've sent a lot of cards sprayed with my perfume and a lipstick kiss as well.
Last Valentine's I sent him, for 2 weeks, pieces of a photo puzzle. The photo was of me just wearing one of his shirts. I kept giving him notes that said "I know you only ever get pieces of me ..." and then I included a few puzzle pieces. I continued that until there was only one piece left, and I surprised him by delivering it in person.
I don't know if any of these ideas are good for you (since you said you didn't want to be too clingy). But, maybe, they'll at least trigger some other ideas.