What is a good way to generate realistic utility curves?
It's somewhat simple, actually. You can just use a Cobb-Douglas with $m+1$ goods available, the last one being leisure. So, you should have something like:

$$U(x_1,x_2,...,x_m,x_{m+1}) = \prod_{i=1}^{m+1} x_i^{\alpha_i}$$

Subject to $\sum_{i=1}^{m+1} \alpha_i = k$, where $k$ is the degree of homogeneity of the utility function. Usually, $k=1$ is considered reasonable.