Possible additional developments in no particular order

 - options to handle quantiles in rounded continuous data like SUDAAN
   does (if I can work out what it does).

 - Score-based confidence intervals for glms

 - Rao-Scott type tests for glms.

 - More general HT estimator for sampling without replacement
 	- using joint inclusion probabilities
	- using population first-order inclusion probabilities and Hartley-Rao approximation
	- using Overton's approximation and sample inclusion probabilities
        [done] using Berger's approximation and sample inclusion probabilities.

 - GEE. 

 - Parametric survival models (you can do these with svymle)

 - linear mixed models?

 - standard errors for survival curves, particularly in two-phase studies

 - an interface to twophase and calibrate for IPTW estimation.

 - Replicate weights for two-phase designs and for multistage designs
   with large sampling fraction (Fukuoka's BBE)

 - parallel processing for replicate weights?
