Evenin' rusSTyEB et al,
I made my own raisers similar to the second of your hyperlinks over 12 years ago and still doing the job well...however, 2 things U should consider. They are if in the unfortunate instance U have a crash in which insurance is involved, are U still covered. Secondly, if your bike has ABS etc post 1997, you will need to re-route the brake hydraulic hose so that it is outside (to the right), of the the right handlebar raiser; orherwise U will overstretch it on full LEFT lock.
Just a thought
Ciao, the can:-)