Actually there is a way to make them bigger, checkboxes just like anything else (even an iframe like a facebook button).
Wrap them in a "zoomed" element:
.double {_x000D_
zoom: 2;_x000D_
transform: scale(2);_x000D_
-ms-transform: scale(2);_x000D_
-webkit-transform: scale(2);_x000D_
-o-transform: scale(2);_x000D_
-moz-transform: scale(2);_x000D_
transform-origin: 0 0;_x000D_
-ms-transform-origin: 0 0;_x000D_
-webkit-transform-origin: 0 0;_x000D_
-o-transform-origin: 0 0;_x000D_
-moz-transform-origin: 0 0;_x000D_
}
_x000D_
<div class="double">_x000D_
<input type="checkbox" name="hello" value="1">_x000D_
</div>
_x000D_
It might look a little bit "rescaled" but it works.
Of course you can make that div float:left and put your label besides it, float:left too.