Lamium maculatum 'Beacon Silver' looks good..
http://www.perennials.com/seep...
http://www.gardenersworld.com/...
I'm seeing some with silver over most lf the leaf also called Beacon Silver, but I came across another. Lamium maculatum 'Chequers' which also looked the same. I found that on the Heritage plant site and it does have stripes in the middle of the leaves, but the flowers are more robust.
http://www.moodysnursery.com/i...
http://www.perennials.com/seep...
However, the description for Beacon Silver is:
"This classic selection forms a spreading patch of small silver leaves with a narrow green edge"
For Chequers:
"This vigorous selection forms a spreading patch of small heart-shaped green leaves with a silvery stripe down the middle"
It would appear to be Lamium maculatum 'Chequers'.
If you search on the site for Lamium iit brings up 15 varieties.
On another site here the description for Chequers is different!
http://woottensplants.co.uk/pl...
That's more or less supported ..
Hmmm!
http://www.sciencephoto.com/me...
http://www.pflanzen-traum.de/p...
http://www.kurtbluemel.com/bot...
http://rockimea.appspot.com/pl...
Chequers looks to be winning!