Well, now you have a few solutions. One is to buy Make the Cut, which utilizes single line fonts (which Silhouette software generally doesn't). Another option is to purchase fonts from the Silhouette Store. This is a newer offering and I've seen fonts that are $2.99 (3 times more than the typical download) and I've also seen fonts that are not the whole font- you might get ABCDE for $2.99 and then pay another $2.99 for the next section, etc. In the words of Cartman, laaaame. Your third option would be to scour the web for thin fonts that don't appear hollow because of their natural thinness- they ARE hollow but the lines are so tight you can't tell. And your last option, color in the font by hand after your machine is done outlining it.
I don't own Make the Cut yet, but I'm thinking about it. I do have 2 fonts from the Silhouette Store and I like them ok, but the price and the sectioned alphabet isn't appealing. And, if I want to hand color in every letter of something, I would just stick the card upside down in my printer and simply print it.
So, I went with option 3 and scoured the web for thin fonts. They are all FREE save 2 and I've compiled the links for you. Aren't I nice? Aren't I lucky that my toddler takes 4 hour naps?
All fonts are 38 point. There are lines at the top where my pen dragged- that is because I lost the popsicle stick that came with my marker holder and was guessing at the pen depth. Not every font you see is going to appear solid- I was testing out a lot and remember, if it's slightly hollow here, it will probably be solid at a smaller point size.
Fonts were drawn using a standard black felt tip pen I found in a desk.