Desk Light

This looks like my Dell keyboard, mostly. If it was the same size it would probably work, but how do you know if it is or not? And how much difference would be significant?

The light on my desk is getting old and the switch is getting cranky. It has a halogen bulb and the shade has no vent so it gets very hot and over the years it has baked the switch housing into near failure. The rest of the lamp is fine, it's just the switch that is failing. I would replace the switch if I could find one, but locating such an animal promises to be a trip down the proverbial rabbit hole, so I've just kind of been limping along.
     Since the switch is unreliable I often find myself typing in the dark which is fine until my fingers lose their place and then when I look down to regain my place I can't see the labels on the keys. This has led me to conclude that all I might really need is a light for my keyboard. I was thinking something low profile that clips along the top edge and casts a 'warm glow' over the keys making the labels readily discernible. No such animal exists. All we have is these little bitty 'book light' things. They might work, but I don't want some mechanical snake sticking his head into my viewspace.
    OK, how about a backlit keyboard? Well, that might work, if it was cheap enough. Keyboards from the recycler cost $3, so I'm not prepared to shell out $80 just to get a little light. Amazon has some for around $20, which is more than a buck and half, but feasible.
    But now we have another problem. Do any of these backlit keyboards have EXACTLY the same layout as the Dell keyboard I have been using for the last decade? The last thing I need right now is to have to adjust to a new keyboard. Plus there are several other computers here that all have Dell keyboards. I might be willing to shell out $20 for one keyboard, but I am certainly not going to replace all of my keyboards. Besides, some of the other people here might be even more resistant to change than I am.
    So, do these backlit keyboards have the same layout as a Dell or not? No way to tell. They certainly don't tell you, and I'm not sure looking at pictures would be enough. Yes, it looks the same, but what if the all the keys are a slightly different size, or that one key you use all the time that is off in the corner is in a slightly different location, just different enough that your finger glances off the side instead of catching the edge and you have to pause and deliberately restrike that one stinking key. That would suck.
    But hey! Maybe Dell sells backlit keyboards. They might, but I didn't find any.
    Where is the Association for Keyboard Layout Certification when you need them?