I think we may be able to do the form submit to generate configs like this:

curl -d "_.rawWorkspaceDir=%24%7BITEM_ROOTDIR%7D%2Fworkspace&_.rawBuildsDir=%24%7BITEM_ROOTDIR%7D%2Fbuilds&system_message=&_.numExecutors=2&_.quietPeriod=5&_.scmCheckoutRetryCount=0&namingStrategy=0&stapler-class=jenkins.model.ProjectNamingStrategy%24DefaultProjectNamingStrategy&stapler-class=jenkins.model.ProjectNamingStrategy%24PatternProjectNamingStrategy&_.namePattern=.*&slaveAgentPort.type=random&stapler-class=hudson.markup.RawHtmlMarkupFormatter&stapler-class=hudson.security.LegacySecurityRealm&stapler-class=hudson.security.HudsonPrivateSecurityRealm&privateRealm.allowsSignup=on&stapler-class=hudson.security.LDAPSecurityRealm&ldap.server=&ldap.rootDN=&ldap.userSearchBase=&ldap.userSearch=&ldap.groupSearchBase=&ldap.managerDN=&ldap.managerPassword=&stapler-class=hudson.security.PAMSecurityRealm&_.serviceName=&authorization=0&stapler-class=hudson.security.AuthorizationStrategy%24Unsecured&stapler-class=hudson.security.LegacyAuthorizationStrategy&stapler-class=hudson.security.FullControlOnceLoggedInAuthorizationStrategy&stapler-class=hudson.security.GlobalMatrixAuthorizationStrategy&stapler-class=hudson.security.ProjectMatrixAuthorizationStrategy&stapler-class=hudson.security.csrf.DefaultCrumbIssuer&name=jobConfigHistory&historyRootDir=&maxHistoryEntries=&excludePattern=queue%7CnodeMonitors%7CUpdateCenter%7Cglobal-build-stats&globalMavenOpts=&stapler-class=hudson.maven.local_repo.DefaultLocalRepositoryLocator&stapler-class=hudson.maven.local_repo.PerExecutorLocalRepositoryLocator&stapler-class=hudson.maven.local_repo.PerJobLocalRepositoryLocator&_.usageStatisticsCollected=on&port.type=random&_.cvsExe=&_.cvspassFile=&svn.workspaceFormat=8&svn.global_excluded_revprop=&svn.storeAuthToDisk=on&shell=&_.url=http%3A%2F%2Flocalhost%3A7070%2F&_.smtpServer=&_.defaultSuffix=&_.adminAddress=address+not+configured+yet+%3Cnobody%40nowhere%3E&_.smtpAuthUserName=&_.smtpAuthPassword=&_.smtpPort=&_.replyToAddress=&_.charset=UTF-8&sendTestMailTo=&log-parser.name=TEI+Log+Parse+Rules&log-parser.path=%2Fvar%2Flib%2Fjenkins%2Fhudson-log-parse-rules&log-parser.name=&log-parser.path=&core%3Aapply=&json=%7B%22rawWorkspaceDir%22%3A+%22%24%7BITEM_ROOTDIR%7D%2Fworkspace%22%2C+%22rawBuildsDir%22%3A+%22%24%7BITEM_ROOTDIR%7D%2Fbuilds%22%2C+%22system_message%22%3A+%22%22%2C+%22%22%3A+%22%22%2C+%22jenkins-model-MasterBuildConfiguration%22%3A+%7B%22numExecutors%22%3A+%222%22%7D%2C+%22jenkins-model-GlobalQuietPeriodConfiguration%22%3A+%7B%22quietPeriod%22%3A+%225%22%7D%2C+%22jenkins-model-GlobalSCMRetryCountConfiguration%22%3A+%7B%22scmCheckoutRetryCount%22%3A+%220%22%7D%2C+%22jenkins-model-GlobalProjectNamingStrategyConfiguration%22%3A+%7B%7D%2C+%22hudson-security-GlobalSecurityConfiguration%22%3A+%7B%7D%2C+%22hudson-security-csrf-GlobalCrumbIssuerConfiguration%22%3A+%7B%7D%2C+%22jenkins-model-GlobalNodePropertiesConfiguration%22%3A+%7B%22globalNodeProperties%22%3A+%7B%7D%7D%2C+%22jenkins-model-GlobalPluginConfiguration%22%3A+%7B%22plugin%22%3A+%7B%22name%22%3A+%22jobConfigHistory%22%2C+%22historyRootDir%22%3A+%22%22%2C+%22maxHistoryEntries%22%3A+%22%22%2C+%22saveSystemConfiguration%22%3A+false%2C+%22excludePattern%22%3A+%22queue%7CnodeMonitors%7CUpdateCenter%7Cglobal-build-stats%22%2C+%22skipDuplicateHistory%22%3A+false%7D%7D%2C+%22hudson-maven-MavenModuleSet%22%3A+%7B%22globalMavenOpts%22%3A+%22%22%2C+%22%22%3A+%220%22%2C+%22localRepository%22%3A+%7B%22stapler-class%22%3A+%22hudson.maven.local_repo.DefaultLocalRepositoryLocator%22%7D%7D%2C+%22hudson-model-UsageStatistics%22%3A+%7B%22usageStatisticsCollected%22%3A+%7B%7D%7D%2C+%22org-jenkinsci-main-modules-sshd-SSHD%22%3A+%7B%22port%22%3A+%7B%22value%22%3A+%22%22%2C+%22type%22%3A+%22random%22%7D%7D%2C+%22hudson-scm-CVSSCM%22%3A+%7B%22cvsExe%22%3A+%22%22%2C+%22cvspassFile%22%3A+%22%22%2C+%22cvs_noCompression%22%3A+false%7D%2C+%22hudson-scm-SubversionSCM%22%3A+%7B%22workspaceFormat%22%3A+%228%22%2C+%22global_excluded_revprop%22%3A+%22%22%2C+%22storeAuthToDisk%22%3A+%7B%7D%7D%2C+%22hudson-tasks-Shell%22%3A+%7B%22shell%22%3A+%22%22%7D%2C+%22hudson-tasks-Mailer%22%3A+%7B%22url%22%3A+%22http%3A%2F%2Flocalhost%3A7070%2F%22%2C+%22smtpServer%22%3A+%22%22%2C+%22defaultSuffix%22%3A+%22%22%2C+%22adminAddress%22%3A+%22address+not+configured+yet+%3Cnobody%40nowhere%3E%22%2C+%22useSsl%22%3A+false%2C+%22smtpPort%22%3A+%22%22%2C+%22replyToAddress%22%3A+%22%22%2C+%22charset%22%3A+%22UTF-8%22%7D%2C+%22hudson-plugins-logparser-LogParserPublisher%22%3A+%7B%22rule%22%3A+%5B%7B%22name%22%3A+%22TEI+Log+Parse+Rules%22%2C+%22path%22%3A+%22%2Fvar%2Flib%2Fjenkins%2Fhudson-log-parse-rules%22%7D%2C+%7B%22name%22%3A+%22%22%2C+%22path%22%3A+%22%22%7D%5D%7D%2C+%22core%3Aapply%22%3A+%22%22%7D&Submit=Save" http://localhost:8080/configSubmit