There was something called a gluco-watch that measured glucose through the skin. It didn't involve anything invasive, but it was notoriously inaccurate. I don't know if there is anything else that doesn't involve strips and lancets.
While it is also "strips", there is a noninvasive method which tests for glucose in urine. It is not as "good" as a glucometer, because the low limit of detection is about 180 mg/dl (10 mmol/l). However, the strips are far cheaper than glucometer test strips, and are non-invasive.
Combined with a periodic HbA1c test (I don't know if you have a Wal-Mart), this test method would be adequate for reasonable glucose control, and would be quite better than no method.
One disadvantage is that the sticks will not indicate low blood sugar. You would have to depend upon symptomatic presentation for these episodes.
However, low blood sugar episodes are quite rarely causative of unfortunate outcomes. It makes you feel "shaky", hungry, and have a headache, but that is about the whole extent of it.
Urine test strips only give a broad range...they are inadequate if you're taking insulin. If not, then they might be sufficient, although one certainly couldn't achieve really tight control by relying on urine testing.
I think there is another problem with urine test strips.
Most bodies will not spill glucose into your urine until the glucose levels is quite high, around 200 I believe. Everyone is different, some people may spill earlier, but I believe most normal people are around 200
So you may not see glucose in your urine at 160, 170, 180 levels which is high.
In other words, urine strips can detect high levels of glucose, but may not be able to measure medium or low levels.
This is what I was explained by my doc and have read elesewhere but may be wrong.
If you search on renal glucose threshold you can find some info on it.