Here is the simple applet that I had put together.
It takes all the steps you list in your LinkedIn Tip: How to Create a One-Click Invitation Link blog post from last year, and simplifies the process for the reader. Now all the have to do is type in their First and Last name, their full LinkedIn Profile URL and click Generate Link. It spits out a full URL that readers and then use to directly invite people to connect with them on LinkedIn.
I've used this great tip of yours to easily add more connections to my LinkedIn. And even took it a step further by purchasing my own short URL and linking to my LinkedIn Profile page and an invitation link:
LinkedIn Profile: Kolby.in
One-Click Invitation Link: add.Kolby.in
Please let me know if you think this might be a valuable addition to your blog post and I would be more than happy to send over the code.
Thanks for taking a look!